In order to set the correct running times during training, more than one indicator is usually applied. I would like to briefly cover three that, in my opinion, should be used.
The first indicator is the way you feel; your capacity to decipher the true degree of intensity. Being able to train at slow, medium, medium-high and fast paces should be simple without necessarily having to be glued to the stopwatch every time you train. Moreover, intensity cannot always be measured by a specific speed. Training load, coupled with other factors, may affect the running times recorded. A speed that is moderated on one day might, therefore, be average on another. Particularly in fartlek, speed play progressions, it is better to pay greater attention to the way it feels.
There are, on the other hand, some sessions where pace accuracy is essential. To get the most out of certain mechanisms, above all aerobic potential and lactic acid tolerance, it is crucial to run at speeds close to the anaerobic threshold and maximum oxygen consumption. In order to do so, you need to work out your own thresholds (using laboratory or field tests) and set training paces to various percentages. Once you have reference running times you can manage them using a stopwatch, which will give you all the information you need in real time.
Using a cardio to set up the correct training speeds is by no means a must-have for running. For those who want to use it as a tutor for training sessions, you should first complete specific tests to connect the frequencies with the reference thresholds and then create training ranges to target the pace you are aiming for. The limit when it comes to the heart (in reference to running, not all sports), is its sensitivity to various factors: the time of day you run at, the season (cold, hot, humid, etc.), tiredness levels, poor resting, any stress brought on by non-sporting activities. Taking the heart as your reference point is not, therefore, always the most accurate indicator.
In summary, I advise using a stopwatch to check the correct running time for the training session, but without paying excessive attention to it. Understanding how it feels and the true degree of intensity is an added bonus when it comes to tweaking sessions more effectively. What’s more, monitoring running times, as well as how it feels, is a great way of understanding yourself even more. As a natural consequence, you will be able to better manage races by drawing on your own body’s resources. Greater awareness equals better performance.